Law schools trying to overturn the murder conviction of a young Detroit man have released a detailed affidavit from a hit man confessing to the four killings.

Professors from the University of Michigan and Northwestern University filed a chilling affidavit in court Wednesday from imprisoned hit man Vincent Smothers, who says he committed the murders, not Davontae Sanford.

Sanford was 14, illiterate and blind in one eye when he walked up to police at the house where four people were killed in his Detroit neighborhood. He immediately became a suspect.

He was 15 when he pleaded guilty in 2008, and was sentenced to prison. But two weeks later, Smothers confessed to those and other killings. Smothers has long expressed a willingness to help Sanford.

Prosecutors say they'll respond in court.